Grizzly or screen for grading material



"w. ROSS.

GRIZZLY (IR-SCREEN FOR GRADING MATERIAL.

APPLICATION FILED MAY 6. 1921 1,414,156. Patented @1225, 1922.-

llillli'll Lb mum-an W. ROSS.

GRIZZLYOR SCREEN FOR GRADINGMATERIAL.

APPLICATION FILED MAY 6. 1 921.

Patented Apr. 25, 1922.

4 SHEETS-SHEET 2.

i i v i I w. R088. GRIZZLY 0R SCREEN FOR GRADING MATERIAL.

APPLICATION FILED MAY 6, I92]- Patented Apr. 25, 1922.

4 SHEETS-SHEET a'.

W. BOSS.

GRIZZLY 0R SCREEN FOR GRADING MATERIAL.

APPLICATION FILED MAY 6| I92]- Patented Apr. 25, 1922'.

4 SHEETSSHEET 4.

ifZf/EVZ? z'am 13035 WILLIAM B085, 01' CHIGAGO,- ILLINOIS.

' GRIZZLY OB SORT-mi FOR GRADING- Specification of Letters Patent.

Patented Apr. 25, 1922- Application mam a, 1921. Serial in. 401,474.

To all whom it may concern:

Be it known that I WILLIAM Ross, :1, subject of the King of (irreat Britain, and a resident of Chicago, in the count of Cook and State of Illinois, have invente a certain new and useful Grizzly or Screen for Grad-' ing Material, of which the following is a specification.

This invention relates to screens for grading material, and relates particularly to what are commonly known as grizzlies and screens, of the general type which forms the subjects-material of U. S. Letters Patent heretofore issued to me, to wit, No.1,321,7 7 3, dated Nov. 11, 1919, and No. 1,332,305, dated March 2nd, 1920.

Grizzlies or screens of the general type to which the invention relates, comprise two sets of bars supported substantially hori-. zontally and which move in closed orbits of different lengths, the orbits of said barscoinciding in the screening zone, in which said bars will be separated b spaces of-predetermined size, said orbits diverging as the bars pass out of the screening zones, thus automatically increasing the distances between bars moving in difi'erent orbits, such spaces attaining maximum size when said bars are traversing the sections of their orbits directly beneath the screening zone, whereby fines which pass through the bars in the screening zone will pass freely through the spaces between said bars when traversing the lower or return portions of their orbits. i

For purposes of convenient reference and to distinguish the bars which form different series and more in difi'erent orbits, the bars which move in the shorter orbit will be referred to as main bars and the bars which move in the longer orbit will be designated displaceable bars.

In addition to retaining the advantages and improvements secured by my said prior patents, the present invention has for its object to still further improve and perfect the construction and operation of ,grizzlies or. screens of the general type specified.

Among specific objects of the present invention, the following may be enumerated;

1. To insure the release anddischarge of pieces'of material which may become lodged or wedged between the bars of the grizzly in the screening zone, as said bars pass out of the screening zone.

2. To provide means for taking up wear resultant elongation of the chain belts WlllCll carry the screen bars with'the teeth of the sprocket wheels to which said chain belts are adjusted.

3.To prevent oversize material from falling through the openings between the bars as they pass out of the.screening zone, due to the enlargement of the s aces between said bars, as they passaroun the sprocket wheels to which the chain belts carrying the same are adjusted.

' 4. To prevent oversize material, particularly of a thin and slabby character, which may pass through the bars inthe screening zone from becoming trapped at the rear inner portion of the screen.

5. To prevent oversize, elongated, thin or .slabby material from passing through the bars in the screening zone with the fines; and

6. To provide a construction whereby pieces of material which may becomelodged or wedged under the lower edges of the top skirt. plates-which protect the sides of the screenwill be -automatically released in the operation of the grizzly or screen.

To attain the foregoing and other objects of the invention, my improved grizzly or screen, comprises the various features, combinations of features and details of construction hereinafter described and claimed.

In the accompanying drawings, in which my invention is fully illustrated,

Figure 1 is a sectional side elevation of a grizzly embodying my invention, the section being taken substantially on the line 11 of Figure 2.

/ Figure 2 is a front View thereof, the

grizzly proper being shown in central, vertical section,

Figure 3 is a fragmentary enlarged scale, of the grizzly proper shown in Fig. 1.

Figure 4 is a view from the right hand side of Fig. 3;

Figure 5 is a sectional side elevation illustrating screening means proper constructed and arranged for effecting certain objects of the invention.

Figure 6 is a sectional elevation on the line 66 of Fig. 5.

Figure 7 is a top plan of screening means proper constructed and arranged for effecting certain objects of the invention; and

Figures 8 and 9 are fragmentary views view, on an 6, respectively, illustrating a modlfication.

on the side frames, is a shaft 2 secured to which are spaced sprocket wheels 3, adjusted to which are chain belts 4.

Secured in said sprocket wheeisvare main grizziy bars 5 and secured to the links of the chain belt are the dispiaceable bars *3. ffire pitch of said main and displaceable bars is the some and the displaceable bars 6 engage marginal notches 7 formed in said sprocket wheel, the displaceabie bars alternating with the main bars and the relation being such that in the screening zone, the orbits of -said main and displaceable bars are substantially coincident.' I

To provide for displacement of the bars 6 relatively to the main bars 5 at the under or return sections of their orbits, the orbit of the displaceable bars 6 is longer than the orbit of the main bars 5, there being, as shown, one more displaceable bar than there are main bars and one more link in the chain belts 4 than there are notches 7 in the sprocket wheels 3. Thus, gravity will cause the chain belts 4: and with them the displaceable bars 6 to sag and hang below the main bars 5 at the under sides of the sprocket wheels 3.

The links of the. chain. belts 4: are articulated end to end and the displaceable bars 6 connected to said chain belts by means of journals 8 formed at'the ends of said displaceable bars which engage correspondng pivot holes formed in the overlapping ends of the links of said chain belts.

In accordance with my present improvements, the link of the chain belts are made in separate sections, the ends of said sections overlapping and being pivotally connected by pivot pins 9 fitted to suitable bearings termed in the overlapping ends of said iinlr sections. 7

Where the chain belts 4 and the displaceable bars 5 are in full engagement with the sprocket wheeis 3, the pivot pins 9 are sup ported in substantial radial alignment with outsi'e of and eccentric to the main bars 5. one that when divergence of the chain belts from the sprocket wheels 3 begins, the d splaces-hie oars 6 will move outwardly an sprocket wheels 3 so as to the *agernent of said displaceabie toe notches 7, on arcs of circles P diverge r-from arcs oi correspond point atwhich their orbits ingcircles described from the axis oi the main cars 5 corresponding to the pivot pins 9, respectively, thus providing correspond.-

ing clearance between the main and disstantiaiiy ra diaily of the socket wheels 4 and are adapted to be secured in different adj usted positions by means of lock nuts, in a ramiliar manner.

Said thrust screws 11 also provide convenient means for adjusting the operative lengths of the chain bolts 4 to compensate for any elongation of said chain belts which may be caused by wear in the pivot joints, whereby exact register of the displaceable bars 6 with the notches 7 in the sprocket Wheels 3 -may be maintained at all times,

effectively preventing jumping of said bars and disengagement thereof from said notches 7. 1

1 In Figs. 5 and 6 of the drawings, I have shown a modified construction in which both the main and the displaceable' bars are carried by sprocket chains and in which both the main and displaceable bars, instead of being connected to their respective chain belts at the pivot joints thereof are secured in lugs or projections formed on link members of said chain belts.

In said modification, the screening zone of" the grizzly is formed by the upper laps or sections of the chain belts, the orbits of which coincide.

With the main and displace-able bars supported in the manner shown, it is obvious that when the' chain belts pass around the sprocket wheels which define opposite ends of their orbits, respectively, the flexure of said chain belts will increase the distance between adjacent bars, which would permit oversize material to fall between said bars in the screening zone, which would become mixed with the lines, thus impairing the uniformity of the screened material.

In accordance with my present invention I contempiate remedying this objectionable feature by a drum upon the shaft 12a which carries the sprocket wheels the disut which, prefers-sly, will be proh longitudinal rules which win end of the screen which may oi pockets in the ear-race ther of adapted to receive any material which may fall between the Screen bars and which will later be discharged upon the tail board for the oversize material when the pockets of said drum containing such oversized'material are inverted as they approach and pass the under side of the drum.

In Figs. 5 and 6 I have also shown a construction for effecting the object of the invention as it relates to preventing oversize material, particularly material of a slabby character from being trapped at the rear end of the lower or return sections of the screen.

In accordance with my present invention, I attain the foregoing object by positioning the rear sprocket Wheels for the chain belts which carry the displaceable bars, in the rear of the corresponding sprocket Wheels for the chain belts which carry the main bars, thereby maintaining spaces of maximum width between the main and displaceable bars until said bars are again brought into position in which their orbits coincide.

Referring now to Figs. 5 and 6 the numerals 12, l3, l and 15 designate sprocket wheel shafts rotatably mounted in suitable bearings on the machine frame, 16, 17, 18 and 19 pairs of sprocket wheels secured to said shafts in spaced relation, 20 and 21 chain belts adjusted to said sprocket wheels, 22 main bars carried by the chain belt 20, and 23 displaceable bars carried by the chain belts 21, said bars being secured in lugs 24 formed on link members of said chain belts 20 and 21 and which project outwardly therefrom. WVith the described construction 1t is obvious that as the bars 22 and 23 pass around the sprocket wheels 16 secured to the shafts 12, the flexure of the chain belts wlll operate to automatically increase the distance between said bars thereby permitting over size'materi'al to fall between the same. To prevent this, a drum 25 is secured to the sprocket shaft 12, the surface of which extends into close proximity to the screen bars as they pass around the sprocket wheels secured to said shaft 12, thus closlng the spaces between said bars.

Said drum may be made plam but will preferably be provided with longitudmal ribs formingpockets 26 in the surface of said drum, the ribs forming said pockets being spaced apart distances substantially equal to the distance between the screen bars as they pass around the sprocket wheels 12, and being so positioned that their rear s1des will extend substantially tangent to the rear sides of. the screen bars as they pass around said drum.

-With the described construction, as said pockets come into inverted position, the contents thereof will be discharged on to the tail board of the screen, thereby efi'ectually preventing oversize material from being carried rearwardly with said screen bars as they pass out of engagement with the sprocket wheels 16, and again becoming mixed with the fines which have passed through the screen section of the grizzly.

With the construction shown in said Figs. 5 and 6, I am also able to efi'ec't the object of the invention as it relates to preventing oversize material from being trapped at the return ends of the lower sections of the screen, thise'nd being attained by locating the sprocket wheels 18 for the chain belt 21 which carry the displaceable bars 23 'at a distance beyond the sprocket wheels 17 for the chain belts 20 which carry the main bars 22, thus maintaining spaces of maximum size between the main and displaceable bars 20 and 21'until said bars again pass into the screening zone.

As the invention relates to preventing oversize, elongated, thin or slabby material from passin through the screen with the fines, I attain. the object of the invention by dividing the spaces between adjacent bars into sections, the dimension of which transversely of the screen is substantially equal to. the distance between adjacent screen bars. This may be done in a simple manner by securing pins 27 in the main and displaceable "bars, the pins secured in different bars being preferably arranged alternately, and said pins being of such length that they will extend into close proximity to adjacent bars,

all as clearly shown in Fig. 4 of the drawlngs.

To be effective, it is necessary that the pins 27 shall be located substantially in the surface defined by the orbits of the main and displaceable bars and to this end, said bars are pinned or otherwise secured in position to support said pins in the desired relation.

As modified means for maintaining spaces of maximum size between the main and dis placeable bars at the return ends of the lower section of the screen, thereby preventing oversize material, which .may pass through the bars in the screening zone with the fines, from becoming trapped at the return end ofthe lower section of the screen instead of sprocket wheels secured to different shafts mounted in spaced relation, as shown in Figs. 5 and 6-I contemplate the use of sprocket wheels of different sizes for supporting the chain belts which carry the main and displaceable bars, respectively, at their return ends, said sprocket wheels being rotatably mounted, respectively, -on offset sections of a non-rotatable shaft.

This modification is shown in'Figs. 8 and 9 of the drawings, in which 28 designates the chain belt which carries the main bars,- 29 the chain belt which carries the displaceable bars, 30 and 31 ofi-set sections of which the chain belts 29 are adjusted, said sprocket wheels 32 being mounted on the sections of the supporting shaft and the sprocket wheels 33 on the shaft sections 31,

and the relation being such that the orbits of the screen bars will coincide inthe screenin zone,

accordance with mypresent invention,

also, I attain the object o the invention as it relates to providing-a construction whereby pieces under the lower edges of the top skirt plates be automatically released in the operation of the grizzly, by making said top skirt plates or such shape that their lower edges will diverge towards the discharge end of the screen, as shown at 34:, Fig. 7, whereby movement or said screen in operation will operate to dislodge pieces of ma terial which have worked under the edges of said top skirt plates, in an obvious manner.

1 claim,

1. In a grizzly of the type specified, the

I combination of main and displaceable bars arranged and which move in closed. orbits, the orbit of said displaceable bars being longer than the orbit of said main bars, said orbits coinciding in the screening zone,-and means for movably supporting said displace, ably bars whereby displacement thereof will be on lines divergent to' circles described from the centers of adjacent rear main bars, substantially as described.

2. In a grizzly of the type specified, the. combination of main and displaceable bars arranged and which move in closedorbits,

the orbit of said displaceable bars being" longer than the orbit of said main bars, said orbits coinciding in the screening zone, and means for movablysupporting said displaceable bars so constructed and arranged that displacement of said bars will be from centers eccentric to and outside of said main bars, substantially as described.

3. In agrizzly of the type specified, the

combination of main and displaceable bars, chain belts which carry said displaceable bars, sprocket wheels to which said chain belts are. adjusted, saiddisplaceable bars being connected to alternate joints of said chain belts and means for supporting the joints of said chain belts intermediate said displaceable bars eccentrics-lily to and outside of the axes of the main bars, substantially as described,

e, In a grizzly the type specified, the combination of main and displaceable bars, belts which carry said dispiacewle bars, sprocket wbeeis to which said baits adjusted, and means for of material which become lodged the operative lengths of said chain belts to compensate for wear in the joints thereof, substantially as described.

5. In a grizzly of the'type specified, the

combination of main and displaceable bars, chain belts which carry said displaceable bars, sprocket wheels to which said chain belts are adjustedand means for adjusting the operative lengths of said chain belts to compensate for wear in the joints thereof, said means comprising flanges formed on said sprocket wheels and thrust screws threaded through said flanges, the outer ends or which engage link members of said chain belts substantially in line with the joints thereof intermediate said displaceable bars, substantially as described.

6. A grizzly substantially as specified in claim 3, in which the joints of the chain belts intermediate the displaceable bars are 'supported by thrust screws threaded through flanges formed on the sprocket wheels to which said chain belts are adjusted, the ends of which bear against members of the sprocket chain substantially in line with said intermediate chain joints, substantially as described.

7. In a grizzly of the type specified, the combination of main and displaceable bars, chain belts which carry said displaceable bars, sprocket wheels to which said chain belts are adjusted, pins secured insaid bars and which project into the spaces between adjacent bars and means to secure bars carrying said ins from turning, substantially as described? a 8.- In a grizzly of the type specified, the combination of main and dlsplaceable bars, chain belts which carry said displaceable bars, sprocket wheels to which said chain belts are adjusted, pins secured in said bars and projecting into the spaces between adjacent. bars, respectively, and means to secure bars carrylng saidplns from turning,

substantially as described. 9. In a grizzly of the type specified, the

combination of main and displaceable bars arranged and which move in closed orbits, the orbit of said displaceablebars being longer" than the orbit of said main bars, said orbits coinciding in the screening zone, the means for supporting said main and displaceable bars comprising, chain belts to which said main and displaceable bars are secured, respectively, sprocket wheels to L 10. A grizzly of the type specified in claim 9, in which the sprocket wheels forthe return ends of the chain belts which carry the displaceable bars, are mounted beyond the orbits of the main bars, substantially as described.

11. In a grizzly of the type specified, the combination of main and displaceable bars arranged and which move in closed orbits, the orbit of said displaceable bars being longer than the orbit of said main bars, said orbits coinciding in the screening zone, and means to prevent oversize material from passing through the spaces between the grizzly bars at the discharge end of the grizzly and becoming intermixed with the fines, substantially as described.

12. A grizzly substantially as specified in claim 11, in which a drum is mounted on the sprocket wheel shaft at the discharge end of the grizzly, the surface of which extends into close proximity to the grizzly bars passing around said sprocket wheels, substantially as described.

13. A grizzly as specified in claim 12, in

which the drum is provided with longitudinal ribs forming series of pockets in the surface of saiddrum, the relation'being such that the grizzly bars passing around said drum will be in substantial alignment with the ribs thereon, substantially as described.

14. A grizzly substantially as specified in claim 13, in which the rear sides of saidribs will extend substantially tangent to the rear sides of the grizzly bars passing around said drum, substantially as described.

15. In a grizzly of the type specified, the combination of main and displaceable bars arranged and which move in closed orbits,

the orbit of said displaceable bars being longer than the orbit of said main bars, said orbits coinciding in the screening zone, and

top skirt plates, the lower edges of which diverge towards the discharge end of the grizzly, substantially as described.

In witness that I claim the foregoing as my invention, I afiix my signature this 3rd day of May, A. D. 1921.

WILLIAM Ross. 

